Can I use a blue aquarium light for my hermit crabs?
Sounds like one of the black lights we use for our crabs. We use our black light all day since our house is fairly cold. I think our hermit crabs get enough light during the day because there’s a large window in the room that lets light in and our crabs have been fine for the last 3 years, so I don’t think you really need a normal light if what you say about the day and night lights is true about their metabolism.